Polymerization of epsilon-caprolactone with maleic anhydride: Synthesis and characterization

High-molecular-weight polymers of epsilon-caprolactone (CL) and maleic anhy dride (MA) with anhydride group content of about 1% wt have been synthesize d and studied. The polymerization reaction was carried out in bulk under ni trogen atmosphere. Stannous octoate (Sn(oct)(2)), and 2,2'-azobisisobutyron itrile (AIBN) were used as a catalyst and an initiator, respectively. A two -level design of experiments was used to study the effect of various condit ions on the characteristics of the copolymer. Reaction time, temperature, a nd concentration ratio of various reactants (two monomers, monomer to catal yst, and monomer to initiator) were the independent variables used, and the dependent variables included the molecular weight and the anhydride conten t in the polymer. Nuclear magnetic resonance (NMR) studies indicate that th e succinic anhydride units were incorporated individually either to the pol ymer chain end or backbone. Anhydride content in the polymer and gel permea tion chromatograph (GPC) studies indicate that the maleic anhydride acts as the true initiating species rather than as a comonomer in the system. (C) 2000 John Wiley & Sons, Inc.